Move email-sending code into EmailService

h/services/__init__.py

@@ -10,6 +10,7 @@
     BulkGroupService,
     BulkLMSStatsService,
 )
+from h.services.email import EmailService
 from h.services.job_queue import JobQueueService
 from h.services.subscription import SubscriptionService
 
@@ -161,3 +162,4 @@ def includeme(config):  # pragma: no cover
     config.register_service_factory(
         "h.services.analytics.analytics_service_factory", name="analytics"
     )
+    config.register_service_factory("h.services.email.factory", iface=EmailService)

h/services/email.py

@@ -0,0 +1,43 @@
+# noqa: A005
+
+import smtplib
+
+import pyramid_mailer
+import pyramid_mailer.message
+from pyramid.request import Request
+from pyramid_mailer import IMailer
+
+from h.tasks.celery import get_task_logger
+
+logger = get_task_logger(__name__)
+
+
+class EmailService:
+    """A service for sending emails."""
+
+    def __init__(self, request: Request, mailer: IMailer) -> None:
+        self._request = request
+        self._mailer = mailer
+
+    def send(
+        self, recipients: list[str], subject: str, body: str, html: str | None = None
+    ):
+        email = pyramid_mailer.message.Message(
+            subject=subject, recipients=recipients, body=body, html=html
+        )
+        if self._request.debug:  # pragma: no cover
+            logger.info("emailing in debug mode: check the `mail/` directory")
+        try:
+            self._mailer.send_immediately(email)
+        except smtplib.SMTPRecipientsRefused as exc:  # pragma: no cover
+            logger.warning(
+                "Recipient was refused when trying to send an email. Does the user have an invalid email address?",
+                exc_info=exc,
+            )
+        except smtplib.SMTPException:
+            raise
+
+
+def factory(_context, request: Request) -> EmailService:
+    mailer = pyramid_mailer.get_mailer(request)
+    return EmailService(request, mailer)

h/tasks/mailer.py

@@ -6,15 +6,11 @@
 
 import smtplib
 
-import pyramid_mailer
-import pyramid_mailer.message
-
-from h.tasks.celery import celery, get_task_logger
+from h.services.email import EmailService
+from h.tasks.celery import celery
 
 __all__ = ("send",)
 
-log = get_task_logger(__name__)
-
 
 @celery.task(bind=True, max_retries=3, acks_late=True)
 def send(self, recipients, subject, body, html=None):
@@ -30,19 +26,9 @@ def send(self, recipients, subject, body, html=None):
     :param body: the body of the email
     :type body: unicode
     """
-    email = pyramid_mailer.message.Message(
-        subject=subject, recipients=recipients, body=body, html=html
-    )
-    mailer = pyramid_mailer.get_mailer(celery.request)
-    if celery.request.debug:  # pragma: no cover
-        log.info("emailing in debug mode: check the `mail/' directory")
+    service = celery.request.find_service(EmailService)
     try:
-        mailer.send_immediately(email)
-    except smtplib.SMTPRecipientsRefused as exc:  # pragma: no cover
-        log.warning(
-            "Recipient was refused when trying to send an email. Does the user have an invalid email address?",
-            exc_info=exc,
-        )
+        service.send(recipients=recipients, subject=subject, body=body, html=html)
     except smtplib.socket.error as exc:
         # Exponential backoff in case the SMTP service is having problems.
         countdown = self.default_retry_delay * 2**self.request.retries

tests/common/fixtures/services.py

@@ -19,6 +19,7 @@
     BulkLMSStatsService,
 )
 from h.services.developer_token import DeveloperTokenService
+from h.services.email import EmailService
 from h.services.flag import FlagService
 from h.services.group import GroupService
 from h.services.group_create import GroupCreateService
@@ -58,6 +59,7 @@
     "bulk_group_service",
     "bulk_stats_service",
     "developer_token_service",
+    "email_service",
     "flag_service",
     "group_create_service",
     "group_delete_service",
@@ -306,3 +308,8 @@ def user_unique_service(mock_service):
 @pytest.fixture
 def user_update_service(mock_service):
     return mock_service(UserUpdateService, name="user_update")
+
+
+@pytest.fixture
+def email_service(mock_service):
+    return mock_service(EmailService)

tests/unit/h/services/email_test.py

@@ -0,0 +1,94 @@
+import smtplib
+from unittest.mock import sentinel
+
+import pytest
+
+from h.services.email import EmailService, factory
+
+
+class TestEmailService:
+    def test_send_creates_email_message(self, email_service, pyramid_mailer):
+        email_service.send(
+            recipients=["[email protected]"],
+            subject="My email subject",
+            body="Some text body",
+        )
+
+        pyramid_mailer.message.Message.assert_called_once_with(
+            recipients=["[email protected]"],
+            subject="My email subject",
+            body="Some text body",
+            html=None,
+        )
+
+    def test_send_creates_email_message_with_html_body(
+        self, email_service, pyramid_mailer
+    ):
+        email_service.send(
+            recipients=["[email protected]"],
+            subject="My email subject",
+            body="Some text body",
+            html="<p>An HTML body</p>",
+        )
+
+        pyramid_mailer.message.Message.assert_called_once_with(
+            recipients=["[email protected]"],
+            subject="My email subject",
+            body="Some text body",
+            html="<p>An HTML body</p>",
+        )
+
+    def test_send_dispatches_email_using_request_mailer(
+        self, email_service, pyramid_mailer
+    ):
+        request_mailer = pyramid_mailer.get_mailer.return_value
+        message = pyramid_mailer.message.Message.return_value
+
+        email_service.send(
+            recipients=["[email protected]"],
+            subject="My email subject",
+            body="Some text body",
+        )
+
+        request_mailer.send_immediately.assert_called_once_with(message)
+
+    def test_raises_smtplib_exception(self, email_service, pyramid_mailer):
+        request_mailer = pyramid_mailer.get_mailer.return_value
+        request_mailer.send_immediately.side_effect = smtplib.SMTPException()
+
+        with pytest.raises(smtplib.SMTPException):
+            email_service.send(
+                recipients=["[email protected]"],
+                subject="My email subject",
+                body="Some text body",
+            )
+
+    @pytest.fixture
+    def pyramid_request(self, pyramid_request):
+        pyramid_request.debug = False
+        return pyramid_request
+
+    @pytest.fixture
+    def email_service(self, pyramid_request, pyramid_mailer):
+        request_mailer = pyramid_mailer.get_mailer.return_value
+        return EmailService(pyramid_request, request_mailer)
+
+
+class TestFactory:
+    def test_it(self, pyramid_request, pyramid_mailer, EmailService):
+        service = factory(sentinel.context, pyramid_request)
+
+        EmailService.assert_called_once_with(
+            request=pyramid_request, mailer=pyramid_mailer.get_mailer.return_value
+        )
+
+        assert service == EmailService.return_value
+
+    @pytest.fixture(autouse=True)
+    def EmailService(self, patch):
+        return patch("h.services.email.EmailService")
+
+
+@pytest.fixture(autouse=True)
+def pyramid_mailer(patch):
+    return patch("h.services.email.pyramid_mailer", autospec=True)

tests/unit/h/tasks/mailer_test.py

@@ -6,72 +6,8 @@
 from h.tasks import mailer
 
 
-@mock.patch("h.tasks.mailer.celery", autospec=True)
-@mock.patch("h.tasks.mailer.pyramid_mailer", autospec=True)
-def test_send_creates_email_message(pyramid_mailer, celery, pyramid_request):
-    celery.request = pyramid_request
-
-    mailer.send(
-        recipients=["[email protected]"],
-        subject="My email subject",
-        body="Some text body",
-    )
-
-    pyramid_mailer.message.Message.assert_called_once_with(
-        subject="My email subject",
-        recipients=["[email protected]"],
-        body="Some text body",
-        html=None,
-    )
-
-
-@mock.patch("h.tasks.mailer.celery", autospec=True)
-@mock.patch("h.tasks.mailer.pyramid_mailer", autospec=True)
-def test_send_creates_email_message_with_html_body(
-    pyramid_mailer, celery, pyramid_request
-):
-    celery.request = pyramid_request
-
-    mailer.send(
-        recipients=["[email protected]"],
-        subject="My email subject",
-        body="Some text body",
-        html="<p>An HTML body</p>",
-    )
-
-    pyramid_mailer.message.Message.assert_called_once_with(
-        subject="My email subject",
-        recipients=["[email protected]"],
-        body="Some text body",
-        html="<p>An HTML body</p>",
-    )
-
-
-@mock.patch("h.tasks.mailer.celery", autospec=True)
-@mock.patch("h.tasks.mailer.pyramid_mailer", autospec=True)
-def test_send_dispatches_email_using_request_mailer(
-    pyramid_mailer, celery, pyramid_request
-):
-    celery.request = pyramid_request
-    request_mailer = pyramid_mailer.get_mailer.return_value
-    message = pyramid_mailer.message.Message.return_value
-
-    mailer.send(
-        recipients=["[email protected]"],
-        subject="My email subject",
-        body="Some text body",
-    )
-
-    pyramid_mailer.get_mailer.assert_called_once_with(pyramid_request)
-    request_mailer.send_immediately.assert_called_once_with(message)
-
-
-@mock.patch("h.tasks.mailer.celery", autospec=True)
-@mock.patch("h.tasks.mailer.pyramid_mailer", autospec=True)
-def test_send_retries_if_mailing_fails(pyramid_mailer, celery, pyramid_request):
-    celery.request = pyramid_request
-    request_mailer = pyramid_mailer.get_mailer.return_value
-    request_mailer.send_immediately.side_effect = SMTPServerDisconnected()
+def test_send_retries_if_mailing_fails(email_service):
+    email_service.send.side_effect = SMTPServerDisconnected()
 
     mailer.send.retry = mock.Mock(spec_set=[])
     mailer.send(
@@ -87,3 +23,10 @@ def test_send_retries_if_mailing_fails(pyramid_mailer, celery, pyramid_request):
 def pyramid_request(pyramid_request):
     pyramid_request.debug = False
     return pyramid_request
+
+
+@pytest.fixture(autouse=True)
+def celery(patch, pyramid_request):
+    celery = patch("h.tasks.mailer.celery")
+    celery.request = pyramid_request
+    return celery